Messages in this thread | | | Date | Tue, 14 Sep 2004 20:55:25 +0200 | From | Roger Luethi <> | Subject | Re: [1/1][PATCH] nproc v2: netlink access to /proc information |
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On Tue, 14 Sep 2004 11:37:36 -0700, Chris Wright wrote: > * William Lee Irwin III (wli@holomorphy.com) wrote: > > On Tue, 14 Sep 2004 08:37:58 -0700, William Lee Irwin III wrote: > > >> No, in general races of the form "permissions were altered after I > > >> checked them" can happen. > > > > On Tue, Sep 14, 2004 at 06:01:50PM +0200, Roger Luethi wrote: > > > Can you make an example? Some scenario where this would be important? > > > > Not particularly. It largely means poorly-coded apps may report gibberish. > > Canonical example is access(2) followed by open(2), not really relevant > in this case. However, exec setuid root app...when do you check, and > when to you fill in data to send back to user? For /proc, this type of > check happens often (see things like may_ptrace_attach and > task_dumpable in fs/proc/base.c).
For nproc, the procedure looks like this: A tool send(2)s a request, credentials are attached to skb. Based on said credentials, the kernel is free to provide (netlink_unicast to originating socket) or withhold information. In this regard, nproc works like other netlink interfaces.
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